Please contact the contributing institution for more information regarding the copyright status of this object.
Description
Mounted on plexiglass stand for display. Elmer T. Cunningham produced this tubular double filament triode vacuum tube, which he called an Audio Tron, around 1916 at his Audio Tron Sales Company in San Francisco. Cunningham started the company, without patent rights, in 1915 to compete with Lee de Forest's spherical Audion. His tubular double-sided design allowed dual filaments, providing longer operating life. Produced in large numbers, with dependable quality, the Audio Tron contributed to the rise in amateur radio interest and provoked de Forest to devise his own tubular audion. Audio Tron Tube also used a more efficient cylindrical plate, rather than a flat plate typical of the audion. A 1916 De Forest suit against Cunningham was settled out of court, and Cunningham continued to produce the Audio Tron, prompting a price war with de Forest on the West Coast. By mid-1916, Otis Moorehead was marketing his Electron Relay Tube, similar to the Audio Tron, cutting further into de Forest's business. Cunningham, whose business was aimed largely at amateurs, discontinued production during World War I.
Type
image
Identifier
88D632EF-8673-4ADB-A1CD-890128373770 2003-1-289
Subject
Audio Tron Sales Company (San Francisco) Audion Triodes Amplifiers (Electronics) Nineteen tens Vacuum-tubes Cunningham, Elmer T
If you're wondering about permissions and what you can do with this item, a good starting point is the "rights information" on this page. See our terms of use for more tips.
Share your story
Has Calisphere helped you advance your research, complete a project, or find something meaningful? We'd love to hear about it; please send us a message.
